The objective of these studies is to provide a detailed account of and correlation of structural and functional relationships of neurons in the somatosensory cortex. We are studying barrels and related structures in layer IV of the mouse and the rat SmI cortex because they have an anatomical constancy and are known to be related to the vibrissae on the contralateral face in a one-to-one manner. The studies are twofold: 1) Using a computer microscope, we are measuring and reconstructing from serial sections, Golgi impregnated neurons in SmI cortex of mice and rats. The sections are counterstained with a Nissl dye to identify cytoarchitectonic boundaries. 2) Using the 2-deosy-D-glucose (2-DG) method we are examining the localization of neurons responding to specified stimuli. The animals of both species are taken from three groups: 1) normal animals, 2) animals subjected to vibrissae damage on different postnatal days, and 3) animals deprived of normal somatic sensory input from birth by chronic removal of the whisker hairs. From these studies we hope to evaluate the effects of disturbing cortical development and sensory deprivation on the normal pattern of intracortical neuronal organization. The results will be related to single unit studies of the barrel cortex from similarly prepared animals.